I think this is an intermediate project. Not that large, but some calibration is needed, a DC coupled scope would be helpful.
no obsolete parts are used (all you had to do was match the transistors of the expo, if needed for less drift of scale).

A lot of people already indicated interest or placed pre-orders in another thread, however, to keep things more traceable i decided to create this new thread dedicated to the 555-VCO PCB offer only.

more soon (pictures, prices, dates)

the VCO should be available end of january 2013.

there will be two PCBs for this project:
i will do an actual "circuit" board (providing MTA-100 connectors for all external connections), and an optional "eurorack" front panel components PCB for those who do nto want to do all the wiring.

and this time i will offer a frontpanel (top notch quality, the same process i use for my fonitronik production modules) - price TBA.
the front panel will be 16HP, giving you enough room for comfortable tweaking (note: you will NOT be able to talk me into 14HP).

so if you wanted to express your interest do it in a way that makes perectly clear what you want, i.e.:
2x circuit PCB
1x eurorack PCB
1x front panel (depending on price)

the pricing of the PCBs:
7.50 EUR/10.-USD each single PCB
10.-EUR/13.-USD front panel eurorack
+ shipping
international: 2.-EUR/3.-USD (1 PCB), 4.-EUR/6.-USD (2+ PCBs)
deutschland: 1.-EUR (1 PCB), 2.-EUR (2+ PCBs)
this is the same price as for the Thomas Henry LFO Controller, and i think this is a very reasonable price...

1)
in the original schematic of the VCO frmo thomas henry we three times a resistor R26, whereas R25 is missing completely.
so here are the values corresponding to the PCB labeling that are not covered correctly by the schematic/parts list:
R25 - 300k
R26 - 39k
R55 - 5.6k

2)
when powering from 12V:
R13 = 2k
R27 = 22k
R33 = 137k

3)
when you have a hard time finding a precision trimmer wit 25k, just use 50k. does the job as well.

4)
C4 is the timing cap. use a nice C0G/NP0 or a mica for better stability.

5)
Parts for the Control PCB
for the pots any vertical mounted 3-pin 9mm pot should do, i used alpha and alps (for the values needed refer to thomas' schematic).
for the jacks i used the PJ301-BM. there is a new high quality version available with berillium copper from
THONK (Europe)
or
ERTHENVAR (USA)

to connect the control board to the cicuit board you will need single row headers and receptables.

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